Feat: add upgrade to app server modelList (#10556)

### Summary
* Add model upgrade to listModel app server endpoint to support
dynamically show model upgrade banner.

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -11938,6 +11938,12 @@
           "supportsPersonality": {
             "default": false,
             "type": "boolean"
+          },
+          "upgrade": {
+            "type": [
+              "string",
+              "null"
+            ]
           }
         },
         "required": [

codex-rs/app-server-protocol/schema/json/v2/ModelListResponse.json

@@ -59,6 +59,12 @@
         "supportsPersonality": {
           "default": false,
           "type": "boolean"
+        },
+        "upgrade": {
+          "type": [
+            "string",
+            "null"
+          ]
         }
       },
       "required": [

codex-rs/app-server-protocol/schema/typescript/v2/Model.ts

@@ -5,4 +5,4 @@ import type { InputModality } from "../InputModality";
 import type { ReasoningEffort } from "../ReasoningEffort";
 import type { ReasoningEffortOption } from "./ReasoningEffortOption";
 
-export type Model = { id: string, model: string, displayName: string, description: string, supportedReasoningEfforts: Array<ReasoningEffortOption>, defaultReasoningEffort: ReasoningEffort, inputModalities: Array<InputModality>, supportsPersonality: boolean, isDefault: boolean, };
+export type Model = { id: string, model: string, upgrade: string | null, displayName: string, description: string, supportedReasoningEfforts: Array<ReasoningEffortOption>, defaultReasoningEffort: ReasoningEffort, inputModalities: Array<InputModality>, supportsPersonality: boolean, isDefault: boolean, };

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -998,6 +998,7 @@ pub struct ModelListParams {
 pub struct Model {
     pub id: String,
     pub model: String,
+    pub upgrade: Option<String>,
     pub display_name: String,
     pub description: String,
     pub supported_reasoning_efforts: Vec<ReasoningEffortOption>,

codex-rs/app-server/README.md

@@ -90,7 +90,7 @@ Example (from OpenAI's official VSCode extension):
 - `turn/interrupt` — request cancellation of an in-flight turn by `(thread_id, turn_id)`; success is an empty `{}` response and the turn finishes with `status: "interrupted"`.
 - `review/start` — kick off Codex’s automated reviewer for a thread; responds like `turn/start` and emits `item/started`/`item/completed` notifications with `enteredReviewMode` and `exitedReviewMode` items, plus a final assistant `agentMessage` containing the review.
 - `command/exec` — run a single command under the server sandbox without starting a thread/turn (handy for utilities and validation).
-- `model/list` — list available models (with reasoning effort options).
+- `model/list` — list available models (with reasoning effort options and optional `upgrade` model ids).
 - `collaborationMode/list` — list available collaboration mode presets (experimental, no pagination).
 - `skills/list` — list skills for one or more `cwd` values (optional `forceReload`).
 - `skills/remote/read` — list public remote skills (**under development; do not call from production clients yet**).

codex-rs/app-server/src/models.rs

@@ -22,6 +22,7 @@ fn model_from_preset(preset: ModelPreset) -> Model {
     Model {
         id: preset.id.to_string(),
         model: preset.model.to_string(),
+        upgrade: preset.upgrade.map(|upgrade| upgrade.id),
         display_name: preset.display_name.to_string(),
         description: preset.description.to_string(),
         supported_reasoning_efforts: reasoning_efforts_from_preset(

codex-rs/app-server/tests/suite/v2/model_list.rs

@@ -51,6 +51,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
         Model {
             id: "gpt-5.2-codex".to_string(),
             model: "gpt-5.2-codex".to_string(),
+            upgrade: None,
             display_name: "gpt-5.2-codex".to_string(),
             description: "Latest frontier agentic coding model.".to_string(),
             supported_reasoning_efforts: vec![
@@ -80,6 +81,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
         Model {
             id: "gpt-5.1-codex-max".to_string(),
             model: "gpt-5.1-codex-max".to_string(),
+            upgrade: Some("gpt-5.2-codex".to_string()),
             display_name: "gpt-5.1-codex-max".to_string(),
             description: "Codex-optimized flagship for deep and fast reasoning.".to_string(),
             supported_reasoning_efforts: vec![
@@ -109,6 +111,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
         Model {
             id: "gpt-5.1-codex-mini".to_string(),
             model: "gpt-5.1-codex-mini".to_string(),
+            upgrade: Some("gpt-5.2-codex".to_string()),
             display_name: "gpt-5.1-codex-mini".to_string(),
             description: "Optimized for codex. Cheaper, faster, but less capable.".to_string(),
             supported_reasoning_efforts: vec![
@@ -130,6 +133,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
         Model {
             id: "gpt-5.2".to_string(),
             model: "gpt-5.2".to_string(),
+            upgrade: Some("gpt-5.2-codex".to_string()),
             display_name: "gpt-5.2".to_string(),
             description:
                 "Latest frontier model with improvements across knowledge, reasoning and coding"

codex-rs/docs/codex_mcp_interface.md

@@ -100,6 +100,7 @@ Each response yields:
   - `defaultReasoningEffort` – suggested effort for the UI
   - `supportsPersonality` – whether the model supports personality-specific instructions
   - `isDefault` – whether the model is recommended for most users
+  - `upgrade` – optional recommended upgrade model id
 - `nextCursor` – pass into the next request to continue paging (optional)
 
 ## Collaboration modes (experimental)